Microsoft sent out a press release earlier today, saying "Xbox 360 gamers worldwide won’t have to wait until March 13, 2009 to get their hands on the highly-anticipated “Resident Evil 5.” The next installment of the landmark survival horror franchise from Capcom will take action to a new level with a two-level, playable demo available exclusively on Xbox 360 for one week beginning Monday, January 26. In the demo, players will have a first glimpse of the fear they will never forget, as “Resident Evil 5” makes daylight just as terrifying as darkness. Additionally, a new exclusive high-definition trailer of the game, shown only at the past Tokyo Game Show in October of 2008, will be made available for download on the Xbox LIVE service on Friday, Jan. 16."

The key thing to note here is the "exclusively on Xbox 360 for one week".  So Sony fans can expect to be able to get their hands on the same Resident Evil 5 demo shortly after.

Resident Evil 5 is the latest entry into Capcom's popular survival horror franchise.  The highly anticipated title is due out March 13th, for the PlayStation 3 and Xbox 360.